236 Culicifuyes 
ones. Culicifuges prepared with grease are more easily applied but are not 
so lasting as those put up with wax. Soft wax preparations, correctly adjusted 
to the temperature in which it is proposed to use them, are most suitable 
for out of doors use, especially in the case of troops. The retarding of volatilisa¬ 
tion caused by the admixture of the active ingredients with wax or grease is 
a distinct advantage, but care must be exercised in respect of the relative 
proportion of active substance to the base. The golden rule is to use as much 
of the active constituent and as small a quantity of the inert base as is 
consistent with convenient application and the prolonging of the period of 
efficiency, not, as most proprietary compounders appear to think, as little as 
possible. 
In choosing a culicifuge for use, the human factor of choice in regard to 
pleasing and unpleasing odours should be as little disregarded as consistent 
with efficiency. Where large quantities are needed cost is an important 
consideration, but must not be allowed to endanger the willing co-operation 
of the individuals it is desired to protect. 
REFERENCE. 
Howard, Dyar and Knab (1912). The Mosquitoes of North and Central America and the 
West Indies , vol. i. pp. 260, 261. Carnegie Institute. Washington. 
